Can we talk thunderbolts?

[ShoestringMariner]

I’m pulling my boat out of storage next week. 1976 Merc 650. I’d like to address some aging wiring issues, but I don’t understand all this “High voltage” stuff, and frankly, I’m afraid to mess with it.

Are there any must do’s or DONT do’s I need to know about? I do not like shocks, jingles or worse.

Can anyone share the coles notes on these motors?

i had a brief chat with a retired marine mechanic who thought they were cats meow (4cyls more than 3cyls) but I didn’t have time to pick his brain

 

[flyingscott]

Very common for the wire insulation to come apart on them. Replace the wires one at a time and have the battery disconnected.

 

[racerone]

That 3 cylinder 650 is not in the top 10 on the hit parade.-----Be careful with your inspections before spending a lot of time / coins on one.

 

[ShoestringMariner]

Thanks guys, I am aware that these motors don’t get much fanfare. The fact they are more scarce than the earlier 4cyl 650’s tells me something. But, after putting a lower unit on it last year and having it run great, I figured I’d run it until it’s used up.

I did did pick up a 70 OMC motor (boo - hiss?) to toy with as a winter project which will be its eventual replacement if decent enough, but for now I’d like to keep this merc in good running condition.